GI Cases 26-50

Case directory 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Case 26

Omental infarction Case findings: Normal appendix Case directory Omental infarction Case findings: Normal appendix Fatty lesion with hyper-attenuating streaks anterior to the cecum Thickening of the peritoneum

Case 27

Axial T1WI Axial T2WI with fat saturation

Axial T1 portal venous enhancement Axial T1 delayed enhancement

Retractile mesenteritis Inhomogeneous mass of soft-tissue density interspersed with areas of fat, arising from the small bowel mesentery Moderate enhancement of the non-fatty aspects of the process Mass surrounds mesenteric vessels and displaces adjacent small bowel loops MR: Mesenteric mass with irregular borders and low T1 SI T2 intermediate signal intensity Ascites in paracolic gutters and between mesenteric folds PV enhancement: mild enhancement with a radiating pattern of strands and enhanced mesenteric vessels penetrating the lesion

Retractile mesenteritis Also called: sclerosing mesenteritis, systemic nodular panniculitis, liposclerotic mesenteritis Represents fibrous evolution of mesenteric panniculitis Associated with: SLE Lymphoma Gardner's syndrome Thoracic mesothelioma Retroperitoneal fibrosis

Retractile mesenteritis MC presents as a single mass Small bowel series: Separation of loops, with kinking and angulation, suggesting a serosal process CT: Mesenteric mass with a variable amount of fat and soft tissue with radiating linear strands reflecting the fibrous reaction of the mesentery May see calcifications MR: Low T1, low or intermediate T2 Mild and gradual contrast enhancement suggesting a fibrotic reaction

Retractile mesenteritis Case directory Retractile mesenteritis DDX: Liposarcoma: invasion of adjacent structures Desmoid tumor: Associated with Gardner's syndrome MC occur in injured or surgically traumatized sites Lymphoma Carcinomatosis

Case 28

Peritoneal tuberculosis Case directory Peritoneal tuberculosis Case findings: Marked inhomogeneous thickening of the anterior peritoneal wall and SB Marked enhancement Mesenteric lymphadenopathy Peritoneal infection can appear as: Wet type Dry type Fibroadhesive type Combination of above types Wet type (this case): high-density ascitic fluid with exudative content and thickened mesentery

Case 29

Intramural hematoma Case findings: Etiology: anticoagulation Case directory Intramural hematoma Case findings: Thickening of jejunal loops Etiology: anticoagulation MC occurs in duodenum

Case 30

Emphysematous cholecystitis Case findings: Gas in GB wall that forms a low-attenuation ring outlining the gallbladder Gas is also seen in the left intrahepatic and extrahepatic biliary ducts DDX: Emphysematous cholecystitis Ascending cholangitis Biliary-enteric fistula Paraduodenal abscess Periappendiceal abscess in malpositioned appendix Gallbladder lipomatosis:  Plain-film mimmick of GB wall gas

Emphysematous cholecystitis Case directory Emphysematous cholecystitis Acute infection of GB wall caused by gas-forming organisms Unlike other biliary tract disorders, MC in men (65-70%) Four proposed pathogenetic factors: Vascular compromise Gallstones Impaired immune protection Infection with gas-forming organisms

History of adenomatous polyposis and fundal gastric polyps Case 31 History of adenomatous polyposis and fundal gastric polyps

Gardner’s syndrome (with desmoid tumors) Case findings: Multiple mesenteric and omental masses, which are ill-defined causing a tethered appearance to the mesentery Bowel is displaced but not obstructed Large pelvic mass Mass in the soft tissues of the lower abdominal wall

Gardner’s syndrome (with desmoid tumors) DDX tethered mesenteric folds: Post-operative changes Post-radiation changes Desmoplastic reaction: carcinoid, peritoneal implants, leiomyosarcoma, lymphoma DDX large solid pelvic mass in adult male: Prostate / bladder / bowel neoplasm Desmoid tumor Malignant fibrous histiocytoma Leiomyosarcoma Neural tumor

Gardner’s syndrome Autosomal dominant Polyposis: Osteomas: MC colon (100%), stomach (5%), SB (<5 Malignant transformation risk is 100% Osteomas: MC mandible, calvarium, maxilla Soft tissue tumors: Desmoid tumor Sebaceous cysts Neurofibroma, fibroma Leiomyoma, lipomas Surgical trauma predisposes Gardner patient to desmoid formation

AD= autosomal dominant, AR= autosomal recessive, NH= nonhereditary Case directory Polyposis syndromes AD= autosomal dominant, AR= autosomal recessive, NH= nonhereditary

Case 32

Cecal and appendiceal adenocarcinoma Case findings: Asymmetric thickening of cecum and ascending colon Inflammatory changes of posterior perirenal fascia extending into right colic gutter Thickened appendix DDX: Appendicitis with phlegmon Cecal malignancy with rupture and associated appendicitis  Cecal diverticulitis Crohn’s disease

Case directory Appendiceal neoplasm Rare to have appendiceal involvement with adenocarcinoma Lymphoma and adenocarcinoma of appendix are less common Appendiceal carcinoid: 90% of all appendiceal tumors are carcinoids MC distal tip of the appendix Produces a solid bulbous swelling 2 to 3 cm in diameter

Case 33

Malignant fibrous histiocytoma Case findings: Mass centered in right retroperitoneum that is separate from right kidney and adrenal gland No clear fat plane is identified between the mass and the right psoas muscle Enhances heterogeneously with areas of non-enhancement (necrosis) DDX: Malignant fibrous histiocytoma Leiomyosarcoma Lymphoma Liposarcoma

Malignant fibrous histiocytoma Case directory Malignant fibrous histiocytoma MC sarcoma in adults, 5th – 7th decades Mesenchymal origin, potential to be in all organs: MC lower extremities (50%) Upper extremities (about 20%) Abdominal cavity, retroperitoneum (20%) > 5 cm at presentation May erode into adjacent bony structures Metastatic disease and local recurrence are common

Case 34

Hepatic angiomyolipoma Case findings: CT: mass in the posterior segment of the right hepatic lobe composed mostly of fatty tissue MC solitary mass in liver Hemorrhage uncommon complication

DDX fatty liver lesion Lipoma Hepatic adenoma Focal fatty infiltration Case directory DDX fatty liver lesion Lipoma Hepatic adenoma Focal fatty infiltration Angiomyolipoma Metastasis (malignant teratoma, liposarcoma) HCC with fatty metamorphosis HCC: well differentiated, hypovascular Angiomyolipoma: hypervascular

Case 35

Mesenteric panniculitis Case directory Mesenteric panniculitis Case findings: CT: hazy infiltration of the mesentery Also called: sclerosing mesenteritis, mesenteric lipodystrophy, and liposclerotic mesenteritis Benign inflammatory condition of the mesentery, which is frequently asymptomatic and self-limiting MC left side of the abdomen along the orientation of the jejunal mesentery

Case 36

Pelvic lipomatosis Case findings: BE: CT: Ascending curvature of the sigmoid colon Elongation and deformity of the rectum by extrinsic compression CT: Deposits of fat in the perivesical and perirectal spaces causing extrinsic compression of the bladder, sigmoid, and rectum

Pelvic lipomatosis DDX tear-drop bladder: Pelvic lipomatosis Case directory Pelvic lipomatosis DDX tear-drop bladder: Pelvic lipomatosis Hypertrophy of the iliopsoas muscles Retroperitoneal fibrosis Large pelvic abscess Large hematoma, usually due to trauma or anticoagulation therapy Collateral venous circulation from IVC obstruction Large iliac artery aneurysms Adenopathy from lymphoma, and prostatic carcinoma

Case 37